This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. xc2xa7119 from an application for A TRIODIC RECTIFIER SWITCH DEVICE earlier filed in the Korean Industrial Property Office on Dec. 26, 2000 and there duly assigned Serial No. 2000-82074.
1. Field of the invention
The present invention relates to a triodic rectifier switch and more particularly to a triodic rectifier switch for a display device.
2. Description of Related Art
A typical triodic rectifier switch (TRS) includes two junction diodes and one resistor. The TRS is one of those used as a switching element of, for example, a flat panel display device such as a liquid crystal display (LCD) device and an organic EL (electroluminescent) display.
The triodic rectifier switch is simpler in manufacturing process and lower in cost than a thin film transistor (TFT) having three terminals. Also, the triodic rectifier switch has advantages in that it can independently control a signal voltage differently from a switching element having two terminals, and it has low leakage current characteristics differently from a switching element having a combination of a diode and a capacitor.
However, such a triodic rectifier switch is at the beginning stage of research and development, and thus used materials and process to manufacture the triodic rectifier switch are not well known yet.
Exemplars of the art are U.S. Pat. No. 6,072,457 issued to Hashimoto et al., for Display and its Driving Method, U.S. Pat. No. 5,909,264 issued to Fujikawa et al., for LCD Device Having a Switching Element with Reduced Size and Capacitance and Method for Fabricating the Same, U.S. Pat. No. 5,952,991 issued to Akiyama, for Liquid Crystal Display, U.S. Pat. No. 5,905,484 issued to Verhulst, for Liquid Crystal Display Device with Control Circuit, U.S. Pat. No. 5,847,797 issued to Van Dijk, for Display Device, U.S. Pat. No. 5,508,591 issued to Kanemori et al., for Active Matrix Display Device, U.S. Pat. No. 5,122,889 issued to Kaneko et al., for Active Matrix Liquid Crystal Display Using MIM Diodes Having Symmetrical Voltage-current Characteristics as Switching Elements, U.S. Pat. No. 4,983,022 issued to Shannon, for Liquid Crystal Display Device, U.S. Pat. No. 5,069,534 issued to Hirai, for Active Matrix Liquid Crystal Display with Series-connected MIM Structures as a Switching Element, U.S. Pat. No. 6,271,050 issued to Akiba et al., for Method of Manufacturing Thin Film Diode, U.S. Pat. No. 5,025,250 issued to Hains, for Matrix Display Device, U.S. Pat. No. 5,014,048 issued to Knapp, for Matrix Display Systems, and U.S. Pat. No. 6,280,273 issued to Codama, for Organic EL Display Device and Method of Making.
For the foregoing reasons, there exists an urgent need for used materials and process to manufacture the triodic rectifier switch so that the triodic rectifier switch may have excellent characteristics as a switching element.
It is therefore an object of the preferred embodiments of the present invention to provide a triodic rectifier switch having excellent characteristics as a switching element.
It is another object to have a switching element that is easy to manufacture.
It is yet another object to have have a switching element of a display device that is inexpensive to manufacture.
In order to achieve the above and other objects, the preferred embodiments of the present invention provide a triodic rectifier switch (TRS) having two diodes and one resistor. Each of the two diodes includes first and second electrodes, the first electrode made of a material having a work function of more than 4.5 eV (electron-volt) and preferably between 4.5 eV and 6.0 eV, the second electrode made of a material having a work function of less than 4.5 eV and preferably between 2.3 eV and 4.5 eV, and a semiconductor layer formed between the first and second electrode.
The first electrode is made of a material selected from a group including ITO (indium tin oxide), Ni, Se, Pt, Os, Ir, Pd, Au, Cu, Ge, Be, Te, and Mo, and the second electrode is made of a material selected from a group including K, Na, Ca, Li, Mg, In, Ta, Pb, Ag, Al, Zn, Sn, Fe, and Cr. The semiconductor is an organic conjugated conducting polymer. The organic conjugated conducting polymer includes xcex2-polymer (Beta-polymer) and PPV (polyphenylenevinylene). The semiconductor includes Si, Poly-Si, a-Si:H, GaAs, and SiC. The semiconductor layer has an n-type conductivity, and the doping layer is an n30-doping layer or a p-type conductivity, and the doping layer is a p+-doping layer. The resistor is made of the same material as the doping layer.
A doping layer may be formed between the semiconductor layer and the second electrode or between the semiconductor layer and the first electrode. A hole transfer layer is formed between the semiconductor layer and the first electrode, and an electron injection layer is formed between the second electrode and semiconductor layer. The diode is one of a junction diode and a schottky diode. A rectification ratio of the diode is more than 104.
The first and second electrodes may also have multiple layers.